1. Field of the Invention
The present invention relates to a tubular insertion system.
2. Description of the Related Art
An endoscope includes an insertion unit. In general, a distal end portion of the insertion unit includes a measuring unit for measuring capacity when the insertion unit is inserted. Such the measuring unit is, for example, a strain gauge (pressure-sensitive sensor).
Such an endoscope is disclosed by, for example, Jpn. Pat. Appln. KOKAI Publication No. H6-154153. In Jpn. Pat. Appln. KOKAI Publication No. H6-154153, a pressure sensitive sensor as a measuring unit is disposed in a distal end portion of an insertion unit of an endoscope, a catheter or the like. The pressure-sensitive sensor detects capacity (pressure-sensitive information). Detection results are useful for operation as operation support information indicating support of operation when the insertion unit is inserted and the insertion unit is bent. The operation includes an insertion operation of the insertion unit, a rotating operation of the insertion unit, and a bending operation of the insertion unit. The operation support information is very important when operating
Jpn. Pat. Appln. KOKAI Publication No. H6-154153 described above, it is necessary for an operator to grasp pressure-sensitive information in the distal end portion indicating operation support information correctly with high precision so that the operator can easily insert the insertion unit.
It is also desirable for the operator to know operation support information such as shape information of the insertion unit other than the pressure-sensitive information so that the operator can easily insert the insertion unit. To acquire such operation support information (shape information of the insertion unit), the operator needs to correctly grasp pressure-sensitive information from all directions.
Thus, Jpn. Pat. Appln. KOKAI Publication No. H6-154153 described above, the pressure-sensitive sensors are suitably disposed like being distributed over the entire distal end portion of the insertion unit. However, it is not easy to dispose many pressure-sensitive sensors in such a manner due to an increasingly thin distal end portion and in terms of limited wiring space in the insertion unit. Moreover, performance of the pressure-sensitive sensor is greatly affected by noise and the arrangement position of the pressure-sensitive sensor.
It is still more difficult to build a sensing system that simultaneously detects various kinds of operation support information.
Thus, there is a possibility that operation support information cannot be acquired easily with high precision.